Disruption of the thoracic aorta is usually fatal without prompt surgical attention. Left recurrent laryngeal nerve paralysis has been reported in approximately 10% of patients who survive long enough to develop a pseudoaneurysm, but the time of onset has rarely been specified. In this study, 50 cases of thoracic aortic trauma were reviewed to determine the incidence and timing of laryngeal paralysis, compared with 50 cases of atherosclerotic aneurysms matched for location. Four patients in the traumatic group were hoarse, and the onset was immediate in 3. Six in the atherosclerotic group became hoarse. Results indicate that laryngeal paralysis following severe trauma can be a very early sign of aortic injury and requires prompt and thorough investigation.